A layer is a visual representation of data from a source. Openlayers supports a wide range of map types and new types can easily be added through the UI or via submodules. See API documentation.

Sources

Openlayers sources belongs to layers and they are representing the layer's data. These are available for free and commercial map tile services like OpenStreetMap or Bing, for OGC sources like WMS or WMTS, and for vector data in formats like GeoJSON or KML. See API documentation.

Styles

Openlayers let you create styles. Then, styles are applied on layers. Styles can be added through the UI or through submodules. See API documentation.

Projections

Projections support lacks in Openlayers 3.x. It is fully supported on the previous 2.x version which is now deprecated.

Provide a new map option that provides a map in a Drupal block. Each map can have its own block.

Openlayers Contextual Links

Provide contextual links to a map so you can edit a map very quickly.

Openlayers Services

Provide a new map options that allows you to embed any map into a web page, Drupal or something else, via an iframe. This is a kind of way to use Drupal as a mapserver for any site.

Openlayers Field

Provide a new field type 'Openlayers' that allows you to display a map in a content type. Only for display, not for input, for that, use Openlayers geofield.
It also includes a field formatter for Addressfield and textfield (core) that will convert any text input into a location and also a formatter that will convert any uploaded files like GPX, KML or GeoJSON into an Openlayers map.

Openlayers 3: dependencies and requirements

Libraries CDN API to use a CDN version of the JS library or the download it manually. You can also use the command 'drush dl-openlayers' to automatically download and install it in your Drupal installation.

Please, keep in mind that the more work we have in the issue queue, the lesser time we have to work on this module, so, to be clear, before posting an issue, use the search functionality. Fixing bugs is notably more efficient if you provide steps to reproduce the bug.